Weitzel et al. Tropical Diseases, Travel Medicine and Vaccines (2018) 4:10 https://doi.org/10.1186/s40794-018-0070-8

CASEREPORT Open Access Imported scrub : first case in South America and review of the literature Thomas Weitzel1,2* , Mabel Aylwin2, Constanza Martínez-Valdebenito3, Ju Jiang4, Jose Manuel Munita2, Luis Thompson2, Katia Abarca3 and Allen L. Richards4,5

Abstract Background: is a neglected vector-borne zoonosis causing life-threatening illnesses, endemic in the Asian-Pacific region and, as recently discovered, in southern Chile. Scrub typhus is rarely reported in travelers, most probably due to the lack of clinical experience and diagnostic tests in non-endemic countries. We report the first case of imported scrub typhus in South America. Case presentation: A 62-year-old tourist from South Korea presented severely ill with fever, rash, and eschar in Santiago, Chile. Laboratory exams showed thrombocytopenia and elevated inflammation parameters, hepatic enzymes, and LDH. With the clinical suspicion of scrub typhus, empirical treatment with doxycycline was initiated and the patient recovered rapidly and without complications. The diagnosis was confirmed by IgM serology and by real-time PCR, which demonstrated infection with (Kawasaki clade). Conclusions: Only due to the emerging clinical experience with endemic South American scrub typhus and the recent implementation of appropriate diagnostic techniques in Chile, were we able to firstly identify and adequately manage a severe case of imported scrub typhus in South America. Physicians attending febrile travelers need to be aware of this , since it requires prompt treatment with doxycycline to avoid complications. Keywords: Arthropod-borne diseases, Scrub typhus, Orientia tsutsugamushi, Travel, Imported infection

Background with substantial mortality [2]. Until recently, scrub ty- Scrub typhus is a vector-borne zoonosis caused by phus was associated with a single species, O. tsutsuga- Orientia species that manifests as an acute febrile mushi, which exclusively occurred within the so-called disease and has a potentially severe outcome [1]. It is ‘Tsutsugamushi Triangle’ ranging from Pakistan in the transmitted by the larval stage of trombiculid West, far-eastern Russia in the East to northern called ‘chiggers’. After the bite of an infective chigger, a Australia in the South. However, recent reports of characteristic necrotic inoculation lesion termed eschar autochthonous cases in the Middle East and southern might develop, which typically contains high bacterial Chile have reshaped this epidemiological paradigm, loads. The microorganism then spreads via lymphatics suggesting a wider geographical distribution [3, 4]. and blood, causing systemic manifestations and labora- Scrub typhus is very rarely diagnosed in travelers, with tory abnormalities such as elevated C-reactive protein a total of < 40 cases reported in the medical literature. (CRP) and liver enzymes [1]. Although widely under-rec- Still, the problem might be under-recognized, since the ognized, scrub typhus is considered the most important initial clinical suspicion relies on the physicians’ experi- rickettsial infection worldwide threatening over a billion ence, routine laboratory tests are largely unavailable, and people and causing more than a million cases per year only few reference laboratories permit a definite diagno- sis by molecular methods and/or culture. Here we report

* Correspondence: [email protected] an Orientia tsutsugamushi infection in a traveler from 1Laboratorio Clínico, Clínica Alemana de Santiago, Facultad de Medicina South Korea visiting Chile, which was confirmed by Clínica Alemana, Universidad del Desarrollo, Av. Vitacura, 5951 Santiago, Chile molecular methods and serology. 2Servicio de Infectología, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile Full list of author information is available at the end of the article

© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Weitzel et al. Tropical Diseases, Travel Medicine and Vaccines (2018) 4:10 Page 2 of 5

Case presentation USA) as well as serological assays (IgM) for EBV, CMV, A 62-year-old South Korean tourist presented with fever, and Parvovirus B19 were all negative. rash, and severe malaise two days after arrival in Chile. Oral treatment with doxycycline (100 mg bid) was He reported flu-like symptoms with chills, headache, initiated in response to clinical suspicion of scrub and myalgia, which had begun five days earlier. The typhus. Blood samples were drawn, the necrotic eschar patient was from Seoul, but had recently visited a farm was removed and placed in 70% alcohol, and a dry swab south of Seoul. At presentation, the patient suffered sample was taken from the base of the unroofed lesion. intense headache and felt severely unwell. He was tachy- The following day, examination of serum by commercial cardic (108 bpm), had an axillar temperature of 38.8 C, ELISA (Scrub Typhus Detect, InBios International Inc., and a generalized, non-pruritic maculopapular rash, Seattle, WA, USA) was positive for IgM and negative for more pronounced on the trunk and sparing palms, soles, IgG antibodies. A commercial indirect IgG immuno- and mucosa (Fig. 1, A and B). On his left posterior thigh, fluorescence test (Fuller Laboratories, Fullerton, CA, there was a painless necrotic lesion with a diameter of USA) utilizing acetone-fixed O. tsutsugamushi strains 6 mm and a surrounding red halo (Fig. 1, C). Complete (Gilliam, Karp, Kato, Boryong) was positive at a dilution blood count showed mild thrombocytopenia (91,000/ of 1:64 for the Karp antigen. DNA preparations from μL), low hemoglobin (13.0 g/dL), and normal leukocytes buffy coat as well as eschar material and swab samples with a left shift (bands, 20%), toxic granulation, and were positive by quantitative real-time PCR (Otsu47) atypical (reactive) lymphocytes. Other laboratory exams targeting the O. tsutsugamushi-specific 47kD protein revealed elevated inflammation parameters (ESR, gene (htrA) using primers and probe described previ- 32 mm/h; CRP, 3.6 mg/dL), slight hyponatremia ously [5]. From the eschar sample, rrs, htrA and 56 kDa (134 mEq/L), elevated hepatic enzymes (AST, 180 U/L; type specific antigen (tsa56) gene fragments were ALT, 161 U/L; GGT 327 U/L; AP, 208 U/L) and LDH successfully amplified using semi-nested PCR assays (718 U/L). A molecular respiratory panel (xTAG® Re- (Table 1). Amplicons were purified and sequenced by spiratory Viral Panel FAST v2; Luminex, Austin, TX, 3500 Genetic Analyzer (Thermo Fisher Scientific, Waltham, MA, USA), the sequences from each primer were assembled with CodonCode Aligner (CodonCode Corporation, Centerville, MA, USA), and the consensus sequence of 1045, 1456 and 1302 bp fragments were obtained for rrs, htrA, and tsa56, respectively. Sequences were deposited in GenBank (accession numbers MG844362 [rrs], MG844360 [htrA], and MG844361 [tsa56]). Blast search (https://blast.ncbi.nlm.nih.gov/ Blast.cgi) revealed that the pathogen was closest to O. tsutsugamushi Kawasaki type strain, with 100% identity for rrs (O. tsutsugamushi Kawasaki) and tsa56, including isolates from Korea (CBNU-2 and IIOC1217) [6] and Japan (Taguchi) [7]. Phylogenetic analysis also showed that the isolate clustered with Kawasaki type strains for both rrs and tsa56, but was not related with the Orientia sp. Chiloe Island isolate recently discovered from Chile (Fig. 2). With antibiotic treatment, fever subsided within 36 h and the patient was discharged after three days.

Discussion Although scrub typhus represents an important public health issue in the Asia-Pacific region and is one of the most severe rickettsial infections, it is almost unrecognized in travelers and poorly covered in web- based information platforms and textbooks of Travel Medicine. A review from 2004 includes ~ 20 cases in Fig. 1 Coarse maculopapular rash of South Korean patient, travelers [8]; since then, < 15 additional patients have predominantly affecting the trunk (a, b), accompanied by been published, all as single case reports or small case characteristic necrotic eschar on the dorsal face of the left thigh (c) series [9–19]. The GeoSentinel network reported only Weitzel et al. Tropical Diseases, Travel Medicine and Vaccines (2018) 4:10 Page 3 of 5

Table 1 Primers and probes used for diagnostic and phylogenetic analysis Primer ID Sequence Annealing temp. PCR Reference 16sU17F AGAGTTTGATCCTGGCTCAG 56 °C First [30] 16sOR1198R TTTCCTATAGTTCCCGGCATT 56 °C First & second 16sO79F ATTAATGCTGAGCTTGCTTAGCAT 56 °C Second Otr47_263F GTGCTAAGAAARGATGATACTTC 54 °C First [31] Otr1780R AAATCGCCTTTAAACTAGATTTACTTATTA 54 °C First & second Otr47F TAAAGGTTAAGTTTATGAAAAAGGCATTT 54 °C Second Otr56_498F AATTAGTTTAGAATGGTTACCAC 54 °C First r56_585F AATGTCTGCGTTGTCGTTGC 54 °C Second r56_2057 TCCACATACACACCTTCAGC 54 °C First & second [32] OtsuFP630 AACTGATTTTATTCAAACTAATGCTGCT 60 °C Real time [5] OtsuRP747 TATGCCTGAGTAAGATACRTGAATRGAATT 60 °C Real time [5] OtsuPR665 6FAM-TGGGTAGCTTTGGTGGACCGATGTTTAATCT-TAMRA 60 °C Real time [5] five confirmed cases among 47,915 ill travelers between diagnostic tests for scrub typhus were unavailable until 1996 and 2008 [20]. Most of these patients were diag- recently, and imported cases have never been described. nosed by serological tests of single (mostly convalescent) In our case, the emerging clinical experience with samples and only few were molecularly confirmed endemic South American scrub typhus [3] and recent (mostly in endemic countries) [18, 19]. In contrast, many implementation of diagnostic techniques in Chile per- experts postulate an increased risk of travel-associated mitted the proper management and rapid diagnostic scrub typhus due to the emergence of ecotourism confirmation of this imported case. (camping, trekking, rafting) in endemic areas [8, 21, 22], Routinely, scrub typhus is diagnosed by serology, which is in accordance with experiences during military either by positive IgM or IgG seroconversion; though operations during World War II and the Vietnam and early cases are often seronegative. Definitive diagnosis Korea conflicts, when scrub typhus affected thousands mostly relies on molecular methods, preferably from of soldiers [23]. The main reasons for the sustained pau- eschar material, which stays positive even after initiation city of reports in Travel Medicine, is most probably the of treatment [24]. As in other severe rickettsial infec- lack of clinical experience and diagnostic tools in many tions, empirical treatment should never be delayed due non-endemic countries. In South America, for example, to diagnostic difficulties. In our case, PCR and serology

Patient from Korea in Chile B A 98 34 O. tsutsugamushi Kawasaki D38625 Patient from Korea in Chile O. tsutsugamushi Taguchi AF173038 O. tsutsugamushi Shimokoshi D38627 100 O. tsutsugamushi clone IIOC1217 KF523361 O. tsutsugamushi Gilliam L36222 84 O. tsutsugamushi CBNU-2 JQ898349 12 O. tsutsugamushi Boryong AM494475 54 O. tsutsugamushi Kawasaki M63383 O. tsutsugamushi Kuroki D38626 92 O. tsutsugamushi Taiwan (Gilliam) DQ485289 80 O. tsutsugamushi Karp D38623 O. tsutsugamushi TA763 U80636

O. tsutsugamushi TA763 AF479299 O. tsutsugamushi Karp AY956315 58 95 77 O. tsutsugamushi Kato D38624 99 O. tsutsugamushi Boryong AM494475 100 O. tsutsugamushi Kuroki M63380 Orientia chuto Dubai HM852447 O. tsutsugamushi Kato M63382 Orientia sp. clone Chiloe Island HM155110 O. tsutsugamushi Shimokoshi M63381 R. prowazekii ME AJ235272 Orientia chuto Dubai HM852448 100 R. rickettsii Iowa CP000766

0.05 0.01 Fig. 2 Phylogenetic analysis of Orientia tsutsugamushi isolate amplified from eschar sample of patient from South Korea. The trees were constructed based on 970 bp rrs (a) and 593 bp tsa56 (b) gene fragments of the patient and O. tsutsugamushi type strains/isolates (GenBank accession numbers are shown next to each agent) using the Maximum Likelihood method with the Tamura-Nei model. Evolutionary analyses were conducted in MEGA7 and the values for the bootstrap test (1000 replicates) are shown next to the branches Weitzel et al. Tropical Diseases, Travel Medicine and Vaccines (2018) 4:10 Page 4 of 5

permitted a timely (but also retrospective) diagnosis, Acknowledgments proving infection with O. tsutsugamushi Kawasaki strain, We wish to thank Lorena Porte for her thoughtful manuscript input. which was acquired in the Imsil district, a region of high Funding scrub typhus incidence in South Korea [25]. This work was partially supported by the Fondo Nacional de Desarrollo Untreated scrub typhus has a high rate of complica- Científico y Tecnológico (FONDECYT N° 1170810) and the Global Emerging tions and mortality, especially in naïve patients [21]. The Infectious Diseases Section, work unit # A1402. immediate start of appropriate antibiotic treatment is Availability of data and materials therefore the main goal of clinical management and All data are presented herein. lowers the risk of severe manifestations. For this, the ’ Disclaimer physicians clinical experience and judgment is crucial. The opinions and assertions contained in this paper are the private views of The most characteristic sign of scrub typhus is a the authors and are not to be construed as official or as reflecting the views necrotic skin lesion (eschar) at the inoculation site. It of the Department of the Navy, the Department of Defense nor the United – States Government. appears in 20 90% of patients, but seems to be more A. L. Richards is an employee of the United States Government. This work frequently present in naïve patients, e.g. travelers [1, 22]. was prepared as a part of his official duties. Title 17 U.S.C. §105 provides that To detect the inconspicuous and painless lesion, a thor- ‘Copyright protection under this title is not available for any work of the United States Government’. Title 17 U.S.C. §101 defines a U.S. Government ough physical exam is essential. If the eschar is not work as a work prepared by a military service member or employee of the detected or patients do not present the lesion, diagnosis U.S. Government as part of that person’s official duties. is often delayed and complications more probable. Scrub Authors’ contributions typhus may also affect domestic travelers. This TW and ALR conceived the report. TW, CM-V, JJ, and ALR drafted the phenomenon has been recognized in Asian countries manuscript and contributed to the literature review. TW, MA, JMM, and LT such as Taiwan [26], and is also an emerging problem in attended the patient. All authors participated in the interpretation of relevant Chilean travelers returning to the central metropolitan results, provided critical edits, and approved the final manuscript. region from trips to endemic regions in southern Chile Ethics approval and consent to participate (unpublished data). The main differential diagnoses in Ethics approval for this case report was not sought as there was no human eschar-positive febrile travelers are spotted fever group subjects study in which to participate. The patient consented that his personal and clinical information was used for scientific and teaching rickettsioses. In our patient, those included Japanese reasons. spotted fever caused by japonica and other endemic rickettsiae endemic in South Korea such as R. Consent for publication The patient consented that information regarding his case was presented in monacensis, R. felis, and R. akari [27, 28]. The centrifu- this manuscript. gal distribution of the rash, sparing palms and soles, was suggestive for scrub typhus, since rickettsial spotted fe- Competing interests vers have a centripetal rash including palms and soles The authors declare that they have no competing interests. [29]. In comparison to the rash of patients with dengue ’ or other arboviral infections, the rash in scrub typhus Publisher sNote Springer Nature remains neutral with regard to jurisdictional claims in has a coarser and more irregular appearance. The pres- published maps and institutional affiliations. ence of atypical lymphocytes might lead to the misdiag- nosis of infective mononucleosis, especially in the Author details 1Laboratorio Clínico, Clínica Alemana de Santiago, Facultad de Medicina presence of lymphadenopathy. Clínica Alemana, Universidad del Desarrollo, Av. Vitacura, 5951 Santiago, Chile. 2Servicio de Infectología, Clínica Alemana de Santiago, Facultad de Conclusions Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile. 3Departamento de Enfermedades Infecciosas e Inmunología Pediátricas, This first case of imported scrub typhus in South America Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile. highlights the need of physicians attending febrile travelers 4Viral and Rickettsial Diseases Department, Naval Medical Research Center, 5 to be aware of this severe rickettsiosis. This includes Silver Spring, MD, USA. Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA. knowledge of the endemic regions in Asia, its emergence in South America, and the recognition of the typical Received: 5 July 2018 Accepted: 8 August 2018 clinical manifestations. 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